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1 | /************************************************************************** | |
2 | * | |
3 | * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA. | |
4 | * Copyright 2016 Intel Corporation | |
5 | * All Rights Reserved. | |
6 | * | |
7 | * Permission is hereby granted, free of charge, to any person obtaining a | |
8 | * copy of this software and associated documentation files (the | |
9 | * "Software"), to deal in the Software without restriction, including | |
10 | * without limitation the rights to use, copy, modify, merge, publish, | |
11 | * distribute, sub license, and/or sell copies of the Software, and to | |
12 | * permit persons to whom the Software is furnished to do so, subject to | |
13 | * the following conditions: | |
14 | * | |
15 | * The above copyright notice and this permission notice (including the | |
16 | * next paragraph) shall be included in all copies or substantial portions | |
17 | * of the Software. | |
18 | * | |
19 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
20 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
21 | * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL | |
22 | * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, | |
23 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR | |
24 | * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE | |
25 | * USE OR OTHER DEALINGS IN THE SOFTWARE. | |
26 | * | |
27 | * | |
28 | **************************************************************************/ | |
29 | ||
30 | /* | |
31 | * Generic simple memory manager implementation. Intended to be used as a base | |
32 | * class implementation for more advanced memory managers. | |
33 | * | |
34 | * Note that the algorithm used is quite simple and there might be substantial | |
35 | * performance gains if a smarter free list is implemented. Currently it is | |
36 | * just an unordered stack of free regions. This could easily be improved if | |
37 | * an RB-tree is used instead. At least if we expect heavy fragmentation. | |
38 | * | |
39 | * Aligned allocations can also see improvement. | |
40 | * | |
41 | * Authors: | |
42 | * Thomas Hellström <thomas-at-tungstengraphics-dot-com> | |
43 | */ | |
44 | ||
45 | #include <drm/drmP.h> | |
46 | #include <drm/drm_mm.h> | |
47 | #include <linux/slab.h> | |
48 | #include <linux/seq_file.h> | |
49 | #include <linux/export.h> | |
50 | #include <linux/interval_tree_generic.h> | |
51 | ||
52 | /** | |
53 | * DOC: Overview | |
54 | * | |
55 | * drm_mm provides a simple range allocator. The drivers are free to use the | |
56 | * resource allocator from the linux core if it suits them, the upside of drm_mm | |
57 | * is that it's in the DRM core. Which means that it's easier to extend for | |
58 | * some of the crazier special purpose needs of gpus. | |
59 | * | |
60 | * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node. | |
61 | * Drivers are free to embed either of them into their own suitable | |
62 | * datastructures. drm_mm itself will not do any memory allocations of its own, | |
63 | * so if drivers choose not to embed nodes they need to still allocate them | |
64 | * themselves. | |
65 | * | |
66 | * The range allocator also supports reservation of preallocated blocks. This is | |
67 | * useful for taking over initial mode setting configurations from the firmware, | |
68 | * where an object needs to be created which exactly matches the firmware's | |
69 | * scanout target. As long as the range is still free it can be inserted anytime | |
70 | * after the allocator is initialized, which helps with avoiding looped | |
71 | * dependencies in the driver load sequence. | |
72 | * | |
73 | * drm_mm maintains a stack of most recently freed holes, which of all | |
74 | * simplistic datastructures seems to be a fairly decent approach to clustering | |
75 | * allocations and avoiding too much fragmentation. This means free space | |
76 | * searches are O(num_holes). Given that all the fancy features drm_mm supports | |
77 | * something better would be fairly complex and since gfx thrashing is a fairly | |
78 | * steep cliff not a real concern. Removing a node again is O(1). | |
79 | * | |
80 | * drm_mm supports a few features: Alignment and range restrictions can be | |
81 | * supplied. Furthermore every &drm_mm_node has a color value (which is just an | |
82 | * opaque unsigned long) which in conjunction with a driver callback can be used | |
83 | * to implement sophisticated placement restrictions. The i915 DRM driver uses | |
84 | * this to implement guard pages between incompatible caching domains in the | |
85 | * graphics TT. | |
86 | * | |
87 | * Two behaviors are supported for searching and allocating: bottom-up and | |
88 | * top-down. The default is bottom-up. Top-down allocation can be used if the | |
89 | * memory area has different restrictions, or just to reduce fragmentation. | |
90 | * | |
91 | * Finally iteration helpers to walk all nodes and all holes are provided as are | |
92 | * some basic allocator dumpers for debugging. | |
93 | * | |
94 | * Note that this range allocator is not thread-safe, drivers need to protect | |
95 | * modifications with their own locking. The idea behind this is that for a full | |
96 | * memory manager additional data needs to be protected anyway, hence internal | |
97 | * locking would be fully redundant. | |
98 | */ | |
99 | ||
100 | #ifdef CONFIG_DRM_DEBUG_MM | |
101 | #include <linux/stackdepot.h> | |
102 | ||
103 | #define STACKDEPTH 32 | |
104 | #define BUFSZ 4096 | |
105 | ||
106 | static noinline void save_stack(struct drm_mm_node *node) | |
107 | { | |
108 | unsigned long entries[STACKDEPTH]; | |
109 | struct stack_trace trace = { | |
110 | .entries = entries, | |
111 | .max_entries = STACKDEPTH, | |
112 | .skip = 1 | |
113 | }; | |
114 | ||
115 | save_stack_trace(&trace); | |
116 | if (trace.nr_entries != 0 && | |
117 | trace.entries[trace.nr_entries-1] == ULONG_MAX) | |
118 | trace.nr_entries--; | |
119 | ||
120 | /* May be called under spinlock, so avoid sleeping */ | |
121 | node->stack = depot_save_stack(&trace, GFP_NOWAIT); | |
122 | } | |
123 | ||
124 | static void show_leaks(struct drm_mm *mm) | |
125 | { | |
126 | struct drm_mm_node *node; | |
127 | unsigned long entries[STACKDEPTH]; | |
128 | char *buf; | |
129 | ||
130 | buf = kmalloc(BUFSZ, GFP_KERNEL); | |
131 | if (!buf) | |
132 | return; | |
133 | ||
134 | list_for_each_entry(node, drm_mm_nodes(mm), node_list) { | |
135 | struct stack_trace trace = { | |
136 | .entries = entries, | |
137 | .max_entries = STACKDEPTH | |
138 | }; | |
139 | ||
140 | if (!node->stack) { | |
141 | DRM_ERROR("node [%08llx + %08llx]: unknown owner\n", | |
142 | node->start, node->size); | |
143 | continue; | |
144 | } | |
145 | ||
146 | depot_fetch_stack(node->stack, &trace); | |
147 | snprint_stack_trace(buf, BUFSZ, &trace, 0); | |
148 | DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s", | |
149 | node->start, node->size, buf); | |
150 | } | |
151 | ||
152 | kfree(buf); | |
153 | } | |
154 | ||
155 | #undef STACKDEPTH | |
156 | #undef BUFSZ | |
157 | #else | |
158 | static void save_stack(struct drm_mm_node *node) { } | |
159 | static void show_leaks(struct drm_mm *mm) { } | |
160 | #endif | |
161 | ||
162 | #define START(node) ((node)->start) | |
163 | #define LAST(node) ((node)->start + (node)->size - 1) | |
164 | ||
165 | INTERVAL_TREE_DEFINE(struct drm_mm_node, rb, | |
166 | u64, __subtree_last, | |
167 | START, LAST, static inline, drm_mm_interval_tree) | |
168 | ||
169 | struct drm_mm_node * | |
170 | __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last) | |
171 | { | |
172 | return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree, | |
173 | start, last) ?: (struct drm_mm_node *)&mm->head_node; | |
174 | } | |
175 | EXPORT_SYMBOL(__drm_mm_interval_first); | |
176 | ||
177 | static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node, | |
178 | struct drm_mm_node *node) | |
179 | { | |
180 | struct drm_mm *mm = hole_node->mm; | |
181 | struct rb_node **link, *rb; | |
182 | struct drm_mm_node *parent; | |
183 | bool leftmost; | |
184 | ||
185 | node->__subtree_last = LAST(node); | |
186 | ||
187 | if (hole_node->allocated) { | |
188 | rb = &hole_node->rb; | |
189 | while (rb) { | |
190 | parent = rb_entry(rb, struct drm_mm_node, rb); | |
191 | if (parent->__subtree_last >= node->__subtree_last) | |
192 | break; | |
193 | ||
194 | parent->__subtree_last = node->__subtree_last; | |
195 | rb = rb_parent(rb); | |
196 | } | |
197 | ||
198 | rb = &hole_node->rb; | |
199 | link = &hole_node->rb.rb_right; | |
200 | leftmost = false; | |
201 | } else { | |
202 | rb = NULL; | |
203 | link = &mm->interval_tree.rb_root.rb_node; | |
204 | leftmost = true; | |
205 | } | |
206 | ||
207 | while (*link) { | |
208 | rb = *link; | |
209 | parent = rb_entry(rb, struct drm_mm_node, rb); | |
210 | if (parent->__subtree_last < node->__subtree_last) | |
211 | parent->__subtree_last = node->__subtree_last; | |
212 | if (node->start < parent->start) { | |
213 | link = &parent->rb.rb_left; | |
214 | } else { | |
215 | link = &parent->rb.rb_right; | |
216 | leftmost = false; | |
217 | } | |
218 | } | |
219 | ||
220 | rb_link_node(&node->rb, rb, link); | |
221 | rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost, | |
222 | &drm_mm_interval_tree_augment); | |
223 | } | |
224 | ||
225 | #define RB_INSERT(root, member, expr) do { \ | |
226 | struct rb_node **link = &root.rb_node, *rb = NULL; \ | |
227 | u64 x = expr(node); \ | |
228 | while (*link) { \ | |
229 | rb = *link; \ | |
230 | if (x < expr(rb_entry(rb, struct drm_mm_node, member))) \ | |
231 | link = &rb->rb_left; \ | |
232 | else \ | |
233 | link = &rb->rb_right; \ | |
234 | } \ | |
235 | rb_link_node(&node->member, rb, link); \ | |
236 | rb_insert_color(&node->member, &root); \ | |
237 | } while (0) | |
238 | ||
239 | #define HOLE_SIZE(NODE) ((NODE)->hole_size) | |
240 | #define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE)) | |
241 | ||
242 | static u64 rb_to_hole_size(struct rb_node *rb) | |
243 | { | |
244 | return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size; | |
245 | } | |
246 | ||
247 | static void insert_hole_size(struct rb_root_cached *root, | |
248 | struct drm_mm_node *node) | |
249 | { | |
250 | struct rb_node **link = &root->rb_root.rb_node, *rb = NULL; | |
251 | u64 x = node->hole_size; | |
252 | bool first = true; | |
253 | ||
254 | while (*link) { | |
255 | rb = *link; | |
256 | if (x > rb_to_hole_size(rb)) { | |
257 | link = &rb->rb_left; | |
258 | } else { | |
259 | link = &rb->rb_right; | |
260 | first = false; | |
261 | } | |
262 | } | |
263 | ||
264 | rb_link_node(&node->rb_hole_size, rb, link); | |
265 | rb_insert_color_cached(&node->rb_hole_size, root, first); | |
266 | } | |
267 | ||
268 | static void add_hole(struct drm_mm_node *node) | |
269 | { | |
270 | struct drm_mm *mm = node->mm; | |
271 | ||
272 | node->hole_size = | |
273 | __drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node); | |
274 | DRM_MM_BUG_ON(!drm_mm_hole_follows(node)); | |
275 | ||
276 | insert_hole_size(&mm->holes_size, node); | |
277 | RB_INSERT(mm->holes_addr, rb_hole_addr, HOLE_ADDR); | |
278 | ||
279 | list_add(&node->hole_stack, &mm->hole_stack); | |
280 | } | |
281 | ||
282 | static void rm_hole(struct drm_mm_node *node) | |
283 | { | |
284 | DRM_MM_BUG_ON(!drm_mm_hole_follows(node)); | |
285 | ||
286 | list_del(&node->hole_stack); | |
287 | rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size); | |
288 | rb_erase(&node->rb_hole_addr, &node->mm->holes_addr); | |
289 | node->hole_size = 0; | |
290 | ||
291 | DRM_MM_BUG_ON(drm_mm_hole_follows(node)); | |
292 | } | |
293 | ||
294 | static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb) | |
295 | { | |
296 | return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size); | |
297 | } | |
298 | ||
299 | static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb) | |
300 | { | |
301 | return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr); | |
302 | } | |
303 | ||
304 | static inline u64 rb_hole_size(struct rb_node *rb) | |
305 | { | |
306 | return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size; | |
307 | } | |
308 | ||
309 | static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size) | |
310 | { | |
311 | struct rb_node *rb = mm->holes_size.rb_root.rb_node; | |
312 | struct drm_mm_node *best = NULL; | |
313 | ||
314 | do { | |
315 | struct drm_mm_node *node = | |
316 | rb_entry(rb, struct drm_mm_node, rb_hole_size); | |
317 | ||
318 | if (size <= node->hole_size) { | |
319 | best = node; | |
320 | rb = rb->rb_right; | |
321 | } else { | |
322 | rb = rb->rb_left; | |
323 | } | |
324 | } while (rb); | |
325 | ||
326 | return best; | |
327 | } | |
328 | ||
329 | static struct drm_mm_node *find_hole(struct drm_mm *mm, u64 addr) | |
330 | { | |
331 | struct rb_node *rb = mm->holes_addr.rb_node; | |
332 | struct drm_mm_node *node = NULL; | |
333 | ||
334 | while (rb) { | |
335 | u64 hole_start; | |
336 | ||
337 | node = rb_hole_addr_to_node(rb); | |
338 | hole_start = __drm_mm_hole_node_start(node); | |
339 | ||
340 | if (addr < hole_start) | |
341 | rb = node->rb_hole_addr.rb_left; | |
342 | else if (addr > hole_start + node->hole_size) | |
343 | rb = node->rb_hole_addr.rb_right; | |
344 | else | |
345 | break; | |
346 | } | |
347 | ||
348 | return node; | |
349 | } | |
350 | ||
351 | static struct drm_mm_node * | |
352 | first_hole(struct drm_mm *mm, | |
353 | u64 start, u64 end, u64 size, | |
354 | enum drm_mm_insert_mode mode) | |
355 | { | |
356 | switch (mode) { | |
357 | default: | |
358 | case DRM_MM_INSERT_BEST: | |
359 | return best_hole(mm, size); | |
360 | ||
361 | case DRM_MM_INSERT_LOW: | |
362 | return find_hole(mm, start); | |
363 | ||
364 | case DRM_MM_INSERT_HIGH: | |
365 | return find_hole(mm, end); | |
366 | ||
367 | case DRM_MM_INSERT_EVICT: | |
368 | return list_first_entry_or_null(&mm->hole_stack, | |
369 | struct drm_mm_node, | |
370 | hole_stack); | |
371 | } | |
372 | } | |
373 | ||
374 | static struct drm_mm_node * | |
375 | next_hole(struct drm_mm *mm, | |
376 | struct drm_mm_node *node, | |
377 | enum drm_mm_insert_mode mode) | |
378 | { | |
379 | switch (mode) { | |
380 | default: | |
381 | case DRM_MM_INSERT_BEST: | |
382 | return rb_hole_size_to_node(rb_prev(&node->rb_hole_size)); | |
383 | ||
384 | case DRM_MM_INSERT_LOW: | |
385 | return rb_hole_addr_to_node(rb_next(&node->rb_hole_addr)); | |
386 | ||
387 | case DRM_MM_INSERT_HIGH: | |
388 | return rb_hole_addr_to_node(rb_prev(&node->rb_hole_addr)); | |
389 | ||
390 | case DRM_MM_INSERT_EVICT: | |
391 | node = list_next_entry(node, hole_stack); | |
392 | return &node->hole_stack == &mm->hole_stack ? NULL : node; | |
393 | } | |
394 | } | |
395 | ||
396 | /** | |
397 | * drm_mm_reserve_node - insert an pre-initialized node | |
398 | * @mm: drm_mm allocator to insert @node into | |
399 | * @node: drm_mm_node to insert | |
400 | * | |
401 | * This functions inserts an already set-up &drm_mm_node into the allocator, | |
402 | * meaning that start, size and color must be set by the caller. All other | |
403 | * fields must be cleared to 0. This is useful to initialize the allocator with | |
404 | * preallocated objects which must be set-up before the range allocator can be | |
405 | * set-up, e.g. when taking over a firmware framebuffer. | |
406 | * | |
407 | * Returns: | |
408 | * 0 on success, -ENOSPC if there's no hole where @node is. | |
409 | */ | |
410 | int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node) | |
411 | { | |
412 | u64 end = node->start + node->size; | |
413 | struct drm_mm_node *hole; | |
414 | u64 hole_start, hole_end; | |
415 | u64 adj_start, adj_end; | |
416 | ||
417 | end = node->start + node->size; | |
418 | if (unlikely(end <= node->start)) | |
419 | return -ENOSPC; | |
420 | ||
421 | /* Find the relevant hole to add our node to */ | |
422 | hole = find_hole(mm, node->start); | |
423 | if (!hole) | |
424 | return -ENOSPC; | |
425 | ||
426 | adj_start = hole_start = __drm_mm_hole_node_start(hole); | |
427 | adj_end = hole_end = hole_start + hole->hole_size; | |
428 | ||
429 | if (mm->color_adjust) | |
430 | mm->color_adjust(hole, node->color, &adj_start, &adj_end); | |
431 | ||
432 | if (adj_start > node->start || adj_end < end) | |
433 | return -ENOSPC; | |
434 | ||
435 | node->mm = mm; | |
436 | ||
437 | list_add(&node->node_list, &hole->node_list); | |
438 | drm_mm_interval_tree_add_node(hole, node); | |
439 | node->allocated = true; | |
440 | node->hole_size = 0; | |
441 | ||
442 | rm_hole(hole); | |
443 | if (node->start > hole_start) | |
444 | add_hole(hole); | |
445 | if (end < hole_end) | |
446 | add_hole(node); | |
447 | ||
448 | save_stack(node); | |
449 | return 0; | |
450 | } | |
451 | EXPORT_SYMBOL(drm_mm_reserve_node); | |
452 | ||
453 | static u64 rb_to_hole_size_or_zero(struct rb_node *rb) | |
454 | { | |
455 | return rb ? rb_to_hole_size(rb) : 0; | |
456 | } | |
457 | ||
458 | /** | |
459 | * drm_mm_insert_node_in_range - ranged search for space and insert @node | |
460 | * @mm: drm_mm to allocate from | |
461 | * @node: preallocate node to insert | |
462 | * @size: size of the allocation | |
463 | * @alignment: alignment of the allocation | |
464 | * @color: opaque tag value to use for this node | |
465 | * @range_start: start of the allowed range for this node | |
466 | * @range_end: end of the allowed range for this node | |
467 | * @mode: fine-tune the allocation search and placement | |
468 | * | |
469 | * The preallocated @node must be cleared to 0. | |
470 | * | |
471 | * Returns: | |
472 | * 0 on success, -ENOSPC if there's no suitable hole. | |
473 | */ | |
474 | int drm_mm_insert_node_in_range(struct drm_mm * const mm, | |
475 | struct drm_mm_node * const node, | |
476 | u64 size, u64 alignment, | |
477 | unsigned long color, | |
478 | u64 range_start, u64 range_end, | |
479 | enum drm_mm_insert_mode mode) | |
480 | { | |
481 | struct drm_mm_node *hole; | |
482 | u64 remainder_mask; | |
483 | bool once; | |
484 | ||
485 | DRM_MM_BUG_ON(range_start >= range_end); | |
486 | ||
487 | if (unlikely(size == 0 || range_end - range_start < size)) | |
488 | return -ENOSPC; | |
489 | ||
490 | if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size) | |
491 | return -ENOSPC; | |
492 | ||
493 | if (alignment <= 1) | |
494 | alignment = 0; | |
495 | ||
496 | once = mode & DRM_MM_INSERT_ONCE; | |
497 | mode &= ~DRM_MM_INSERT_ONCE; | |
498 | ||
499 | remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0; | |
500 | for (hole = first_hole(mm, range_start, range_end, size, mode); | |
501 | hole; | |
502 | hole = once ? NULL : next_hole(mm, hole, mode)) { | |
503 | u64 hole_start = __drm_mm_hole_node_start(hole); | |
504 | u64 hole_end = hole_start + hole->hole_size; | |
505 | u64 adj_start, adj_end; | |
506 | u64 col_start, col_end; | |
507 | ||
508 | if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end) | |
509 | break; | |
510 | ||
511 | if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start) | |
512 | break; | |
513 | ||
514 | col_start = hole_start; | |
515 | col_end = hole_end; | |
516 | if (mm->color_adjust) | |
517 | mm->color_adjust(hole, color, &col_start, &col_end); | |
518 | ||
519 | adj_start = max(col_start, range_start); | |
520 | adj_end = min(col_end, range_end); | |
521 | ||
522 | if (adj_end <= adj_start || adj_end - adj_start < size) | |
523 | continue; | |
524 | ||
525 | if (mode == DRM_MM_INSERT_HIGH) | |
526 | adj_start = adj_end - size; | |
527 | ||
528 | if (alignment) { | |
529 | u64 rem; | |
530 | ||
531 | if (likely(remainder_mask)) | |
532 | rem = adj_start & remainder_mask; | |
533 | else | |
534 | div64_u64_rem(adj_start, alignment, &rem); | |
535 | if (rem) { | |
536 | adj_start -= rem; | |
537 | if (mode != DRM_MM_INSERT_HIGH) | |
538 | adj_start += alignment; | |
539 | ||
540 | if (adj_start < max(col_start, range_start) || | |
541 | min(col_end, range_end) - adj_start < size) | |
542 | continue; | |
543 | ||
544 | if (adj_end <= adj_start || | |
545 | adj_end - adj_start < size) | |
546 | continue; | |
547 | } | |
548 | } | |
549 | ||
550 | node->mm = mm; | |
551 | node->size = size; | |
552 | node->start = adj_start; | |
553 | node->color = color; | |
554 | node->hole_size = 0; | |
555 | ||
556 | list_add(&node->node_list, &hole->node_list); | |
557 | drm_mm_interval_tree_add_node(hole, node); | |
558 | node->allocated = true; | |
559 | ||
560 | rm_hole(hole); | |
561 | if (adj_start > hole_start) | |
562 | add_hole(hole); | |
563 | if (adj_start + size < hole_end) | |
564 | add_hole(node); | |
565 | ||
566 | save_stack(node); | |
567 | return 0; | |
568 | } | |
569 | ||
570 | return -ENOSPC; | |
571 | } | |
572 | EXPORT_SYMBOL(drm_mm_insert_node_in_range); | |
573 | ||
574 | /** | |
575 | * drm_mm_remove_node - Remove a memory node from the allocator. | |
576 | * @node: drm_mm_node to remove | |
577 | * | |
578 | * This just removes a node from its drm_mm allocator. The node does not need to | |
579 | * be cleared again before it can be re-inserted into this or any other drm_mm | |
580 | * allocator. It is a bug to call this function on a unallocated node. | |
581 | */ | |
582 | void drm_mm_remove_node(struct drm_mm_node *node) | |
583 | { | |
584 | struct drm_mm *mm = node->mm; | |
585 | struct drm_mm_node *prev_node; | |
586 | ||
587 | DRM_MM_BUG_ON(!node->allocated); | |
588 | DRM_MM_BUG_ON(node->scanned_block); | |
589 | ||
590 | prev_node = list_prev_entry(node, node_list); | |
591 | ||
592 | if (drm_mm_hole_follows(node)) | |
593 | rm_hole(node); | |
594 | ||
595 | drm_mm_interval_tree_remove(node, &mm->interval_tree); | |
596 | list_del(&node->node_list); | |
597 | node->allocated = false; | |
598 | ||
599 | if (drm_mm_hole_follows(prev_node)) | |
600 | rm_hole(prev_node); | |
601 | add_hole(prev_node); | |
602 | } | |
603 | EXPORT_SYMBOL(drm_mm_remove_node); | |
604 | ||
605 | /** | |
606 | * drm_mm_replace_node - move an allocation from @old to @new | |
607 | * @old: drm_mm_node to remove from the allocator | |
608 | * @new: drm_mm_node which should inherit @old's allocation | |
609 | * | |
610 | * This is useful for when drivers embed the drm_mm_node structure and hence | |
611 | * can't move allocations by reassigning pointers. It's a combination of remove | |
612 | * and insert with the guarantee that the allocation start will match. | |
613 | */ | |
614 | void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) | |
615 | { | |
616 | struct drm_mm *mm = old->mm; | |
617 | ||
618 | DRM_MM_BUG_ON(!old->allocated); | |
619 | ||
620 | *new = *old; | |
621 | ||
622 | list_replace(&old->node_list, &new->node_list); | |
623 | rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree); | |
624 | ||
625 | if (drm_mm_hole_follows(old)) { | |
626 | list_replace(&old->hole_stack, &new->hole_stack); | |
627 | rb_replace_node_cached(&old->rb_hole_size, | |
628 | &new->rb_hole_size, | |
629 | &mm->holes_size); | |
630 | rb_replace_node(&old->rb_hole_addr, | |
631 | &new->rb_hole_addr, | |
632 | &mm->holes_addr); | |
633 | } | |
634 | ||
635 | old->allocated = false; | |
636 | new->allocated = true; | |
637 | } | |
638 | EXPORT_SYMBOL(drm_mm_replace_node); | |
639 | ||
640 | /** | |
641 | * DOC: lru scan roster | |
642 | * | |
643 | * Very often GPUs need to have continuous allocations for a given object. When | |
644 | * evicting objects to make space for a new one it is therefore not most | |
645 | * efficient when we simply start to select all objects from the tail of an LRU | |
646 | * until there's a suitable hole: Especially for big objects or nodes that | |
647 | * otherwise have special allocation constraints there's a good chance we evict | |
648 | * lots of (smaller) objects unnecessarily. | |
649 | * | |
650 | * The DRM range allocator supports this use-case through the scanning | |
651 | * interfaces. First a scan operation needs to be initialized with | |
652 | * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds | |
653 | * objects to the roster, probably by walking an LRU list, but this can be | |
654 | * freely implemented. Eviction candiates are added using | |
655 | * drm_mm_scan_add_block() until a suitable hole is found or there are no | |
656 | * further evictable objects. Eviction roster metadata is tracked in &struct | |
657 | * drm_mm_scan. | |
658 | * | |
659 | * The driver must walk through all objects again in exactly the reverse | |
660 | * order to restore the allocator state. Note that while the allocator is used | |
661 | * in the scan mode no other operation is allowed. | |
662 | * | |
663 | * Finally the driver evicts all objects selected (drm_mm_scan_remove_block() | |
664 | * reported true) in the scan, and any overlapping nodes after color adjustment | |
665 | * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and | |
666 | * since freeing a node is also O(1) the overall complexity is | |
667 | * O(scanned_objects). So like the free stack which needs to be walked before a | |
668 | * scan operation even begins this is linear in the number of objects. It | |
669 | * doesn't seem to hurt too badly. | |
670 | */ | |
671 | ||
672 | /** | |
673 | * drm_mm_scan_init_with_range - initialize range-restricted lru scanning | |
674 | * @scan: scan state | |
675 | * @mm: drm_mm to scan | |
676 | * @size: size of the allocation | |
677 | * @alignment: alignment of the allocation | |
678 | * @color: opaque tag value to use for the allocation | |
679 | * @start: start of the allowed range for the allocation | |
680 | * @end: end of the allowed range for the allocation | |
681 | * @mode: fine-tune the allocation search and placement | |
682 | * | |
683 | * This simply sets up the scanning routines with the parameters for the desired | |
684 | * hole. | |
685 | * | |
686 | * Warning: | |
687 | * As long as the scan list is non-empty, no other operations than | |
688 | * adding/removing nodes to/from the scan list are allowed. | |
689 | */ | |
690 | void drm_mm_scan_init_with_range(struct drm_mm_scan *scan, | |
691 | struct drm_mm *mm, | |
692 | u64 size, | |
693 | u64 alignment, | |
694 | unsigned long color, | |
695 | u64 start, | |
696 | u64 end, | |
697 | enum drm_mm_insert_mode mode) | |
698 | { | |
699 | DRM_MM_BUG_ON(start >= end); | |
700 | DRM_MM_BUG_ON(!size || size > end - start); | |
701 | DRM_MM_BUG_ON(mm->scan_active); | |
702 | ||
703 | scan->mm = mm; | |
704 | ||
705 | if (alignment <= 1) | |
706 | alignment = 0; | |
707 | ||
708 | scan->color = color; | |
709 | scan->alignment = alignment; | |
710 | scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0; | |
711 | scan->size = size; | |
712 | scan->mode = mode; | |
713 | ||
714 | DRM_MM_BUG_ON(end <= start); | |
715 | scan->range_start = start; | |
716 | scan->range_end = end; | |
717 | ||
718 | scan->hit_start = U64_MAX; | |
719 | scan->hit_end = 0; | |
720 | } | |
721 | EXPORT_SYMBOL(drm_mm_scan_init_with_range); | |
722 | ||
723 | /** | |
724 | * drm_mm_scan_add_block - add a node to the scan list | |
725 | * @scan: the active drm_mm scanner | |
726 | * @node: drm_mm_node to add | |
727 | * | |
728 | * Add a node to the scan list that might be freed to make space for the desired | |
729 | * hole. | |
730 | * | |
731 | * Returns: | |
732 | * True if a hole has been found, false otherwise. | |
733 | */ | |
734 | bool drm_mm_scan_add_block(struct drm_mm_scan *scan, | |
735 | struct drm_mm_node *node) | |
736 | { | |
737 | struct drm_mm *mm = scan->mm; | |
738 | struct drm_mm_node *hole; | |
739 | u64 hole_start, hole_end; | |
740 | u64 col_start, col_end; | |
741 | u64 adj_start, adj_end; | |
742 | ||
743 | DRM_MM_BUG_ON(node->mm != mm); | |
744 | DRM_MM_BUG_ON(!node->allocated); | |
745 | DRM_MM_BUG_ON(node->scanned_block); | |
746 | node->scanned_block = true; | |
747 | mm->scan_active++; | |
748 | ||
749 | /* Remove this block from the node_list so that we enlarge the hole | |
750 | * (distance between the end of our previous node and the start of | |
751 | * or next), without poisoning the link so that we can restore it | |
752 | * later in drm_mm_scan_remove_block(). | |
753 | */ | |
754 | hole = list_prev_entry(node, node_list); | |
755 | DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node); | |
756 | __list_del_entry(&node->node_list); | |
757 | ||
758 | hole_start = __drm_mm_hole_node_start(hole); | |
759 | hole_end = __drm_mm_hole_node_end(hole); | |
760 | ||
761 | col_start = hole_start; | |
762 | col_end = hole_end; | |
763 | if (mm->color_adjust) | |
764 | mm->color_adjust(hole, scan->color, &col_start, &col_end); | |
765 | ||
766 | adj_start = max(col_start, scan->range_start); | |
767 | adj_end = min(col_end, scan->range_end); | |
768 | if (adj_end <= adj_start || adj_end - adj_start < scan->size) | |
769 | return false; | |
770 | ||
771 | if (scan->mode == DRM_MM_INSERT_HIGH) | |
772 | adj_start = adj_end - scan->size; | |
773 | ||
774 | if (scan->alignment) { | |
775 | u64 rem; | |
776 | ||
777 | if (likely(scan->remainder_mask)) | |
778 | rem = adj_start & scan->remainder_mask; | |
779 | else | |
780 | div64_u64_rem(adj_start, scan->alignment, &rem); | |
781 | if (rem) { | |
782 | adj_start -= rem; | |
783 | if (scan->mode != DRM_MM_INSERT_HIGH) | |
784 | adj_start += scan->alignment; | |
785 | if (adj_start < max(col_start, scan->range_start) || | |
786 | min(col_end, scan->range_end) - adj_start < scan->size) | |
787 | return false; | |
788 | ||
789 | if (adj_end <= adj_start || | |
790 | adj_end - adj_start < scan->size) | |
791 | return false; | |
792 | } | |
793 | } | |
794 | ||
795 | scan->hit_start = adj_start; | |
796 | scan->hit_end = adj_start + scan->size; | |
797 | ||
798 | DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end); | |
799 | DRM_MM_BUG_ON(scan->hit_start < hole_start); | |
800 | DRM_MM_BUG_ON(scan->hit_end > hole_end); | |
801 | ||
802 | return true; | |
803 | } | |
804 | EXPORT_SYMBOL(drm_mm_scan_add_block); | |
805 | ||
806 | /** | |
807 | * drm_mm_scan_remove_block - remove a node from the scan list | |
808 | * @scan: the active drm_mm scanner | |
809 | * @node: drm_mm_node to remove | |
810 | * | |
811 | * Nodes **must** be removed in exactly the reverse order from the scan list as | |
812 | * they have been added (e.g. using list_add() as they are added and then | |
813 | * list_for_each() over that eviction list to remove), otherwise the internal | |
814 | * state of the memory manager will be corrupted. | |
815 | * | |
816 | * When the scan list is empty, the selected memory nodes can be freed. An | |
817 | * immediately following drm_mm_insert_node_in_range_generic() or one of the | |
818 | * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return | |
819 | * the just freed block (because its at the top of the free_stack list). | |
820 | * | |
821 | * Returns: | |
822 | * True if this block should be evicted, false otherwise. Will always | |
823 | * return false when no hole has been found. | |
824 | */ | |
825 | bool drm_mm_scan_remove_block(struct drm_mm_scan *scan, | |
826 | struct drm_mm_node *node) | |
827 | { | |
828 | struct drm_mm_node *prev_node; | |
829 | ||
830 | DRM_MM_BUG_ON(node->mm != scan->mm); | |
831 | DRM_MM_BUG_ON(!node->scanned_block); | |
832 | node->scanned_block = false; | |
833 | ||
834 | DRM_MM_BUG_ON(!node->mm->scan_active); | |
835 | node->mm->scan_active--; | |
836 | ||
837 | /* During drm_mm_scan_add_block() we decoupled this node leaving | |
838 | * its pointers intact. Now that the caller is walking back along | |
839 | * the eviction list we can restore this block into its rightful | |
840 | * place on the full node_list. To confirm that the caller is walking | |
841 | * backwards correctly we check that prev_node->next == node->next, | |
842 | * i.e. both believe the same node should be on the other side of the | |
843 | * hole. | |
844 | */ | |
845 | prev_node = list_prev_entry(node, node_list); | |
846 | DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) != | |
847 | list_next_entry(node, node_list)); | |
848 | list_add(&node->node_list, &prev_node->node_list); | |
849 | ||
850 | return (node->start + node->size > scan->hit_start && | |
851 | node->start < scan->hit_end); | |
852 | } | |
853 | EXPORT_SYMBOL(drm_mm_scan_remove_block); | |
854 | ||
855 | /** | |
856 | * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole | |
857 | * @scan: drm_mm scan with target hole | |
858 | * | |
859 | * After completing an eviction scan and removing the selected nodes, we may | |
860 | * need to remove a few more nodes from either side of the target hole if | |
861 | * mm.color_adjust is being used. | |
862 | * | |
863 | * Returns: | |
864 | * A node to evict, or NULL if there are no overlapping nodes. | |
865 | */ | |
866 | struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan) | |
867 | { | |
868 | struct drm_mm *mm = scan->mm; | |
869 | struct drm_mm_node *hole; | |
870 | u64 hole_start, hole_end; | |
871 | ||
872 | DRM_MM_BUG_ON(list_empty(&mm->hole_stack)); | |
873 | ||
874 | if (!mm->color_adjust) | |
875 | return NULL; | |
876 | ||
877 | /* | |
878 | * The hole found during scanning should ideally be the first element | |
879 | * in the hole_stack list, but due to side-effects in the driver it | |
880 | * may not be. | |
881 | */ | |
882 | list_for_each_entry(hole, &mm->hole_stack, hole_stack) { | |
883 | hole_start = __drm_mm_hole_node_start(hole); | |
884 | hole_end = hole_start + hole->hole_size; | |
885 | ||
886 | if (hole_start <= scan->hit_start && | |
887 | hole_end >= scan->hit_end) | |
888 | break; | |
889 | } | |
890 | ||
891 | /* We should only be called after we found the hole previously */ | |
892 | DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack); | |
893 | if (unlikely(&hole->hole_stack == &mm->hole_stack)) | |
894 | return NULL; | |
895 | ||
896 | DRM_MM_BUG_ON(hole_start > scan->hit_start); | |
897 | DRM_MM_BUG_ON(hole_end < scan->hit_end); | |
898 | ||
899 | mm->color_adjust(hole, scan->color, &hole_start, &hole_end); | |
900 | if (hole_start > scan->hit_start) | |
901 | return hole; | |
902 | if (hole_end < scan->hit_end) | |
903 | return list_next_entry(hole, node_list); | |
904 | ||
905 | return NULL; | |
906 | } | |
907 | EXPORT_SYMBOL(drm_mm_scan_color_evict); | |
908 | ||
909 | /** | |
910 | * drm_mm_init - initialize a drm-mm allocator | |
911 | * @mm: the drm_mm structure to initialize | |
912 | * @start: start of the range managed by @mm | |
913 | * @size: end of the range managed by @mm | |
914 | * | |
915 | * Note that @mm must be cleared to 0 before calling this function. | |
916 | */ | |
917 | void drm_mm_init(struct drm_mm *mm, u64 start, u64 size) | |
918 | { | |
919 | DRM_MM_BUG_ON(start + size <= start); | |
920 | ||
921 | mm->color_adjust = NULL; | |
922 | ||
923 | INIT_LIST_HEAD(&mm->hole_stack); | |
924 | mm->interval_tree = RB_ROOT_CACHED; | |
925 | mm->holes_size = RB_ROOT_CACHED; | |
926 | mm->holes_addr = RB_ROOT; | |
927 | ||
928 | /* Clever trick to avoid a special case in the free hole tracking. */ | |
929 | INIT_LIST_HEAD(&mm->head_node.node_list); | |
930 | mm->head_node.allocated = false; | |
931 | mm->head_node.mm = mm; | |
932 | mm->head_node.start = start + size; | |
933 | mm->head_node.size = -size; | |
934 | add_hole(&mm->head_node); | |
935 | ||
936 | mm->scan_active = 0; | |
937 | } | |
938 | EXPORT_SYMBOL(drm_mm_init); | |
939 | ||
940 | /** | |
941 | * drm_mm_takedown - clean up a drm_mm allocator | |
942 | * @mm: drm_mm allocator to clean up | |
943 | * | |
944 | * Note that it is a bug to call this function on an allocator which is not | |
945 | * clean. | |
946 | */ | |
947 | void drm_mm_takedown(struct drm_mm *mm) | |
948 | { | |
949 | if (WARN(!drm_mm_clean(mm), | |
950 | "Memory manager not clean during takedown.\n")) | |
951 | show_leaks(mm); | |
952 | } | |
953 | EXPORT_SYMBOL(drm_mm_takedown); | |
954 | ||
955 | static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry) | |
956 | { | |
957 | u64 start, size; | |
958 | ||
959 | size = entry->hole_size; | |
960 | if (size) { | |
961 | start = drm_mm_hole_node_start(entry); | |
962 | drm_printf(p, "%#018llx-%#018llx: %llu: free\n", | |
963 | start, start + size, size); | |
964 | } | |
965 | ||
966 | return size; | |
967 | } | |
968 | /** | |
969 | * drm_mm_print - print allocator state | |
970 | * @mm: drm_mm allocator to print | |
971 | * @p: DRM printer to use | |
972 | */ | |
973 | void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p) | |
974 | { | |
975 | const struct drm_mm_node *entry; | |
976 | u64 total_used = 0, total_free = 0, total = 0; | |
977 | ||
978 | total_free += drm_mm_dump_hole(p, &mm->head_node); | |
979 | ||
980 | drm_mm_for_each_node(entry, mm) { | |
981 | drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start, | |
982 | entry->start + entry->size, entry->size); | |
983 | total_used += entry->size; | |
984 | total_free += drm_mm_dump_hole(p, entry); | |
985 | } | |
986 | total = total_free + total_used; | |
987 | ||
988 | drm_printf(p, "total: %llu, used %llu free %llu\n", total, | |
989 | total_used, total_free); | |
990 | } | |
991 | EXPORT_SYMBOL(drm_mm_print); |